But you must start these medical therapies before you lose all your hair. McAndrews likens it to brushing your teeth, in that both are preventative measures. “The sooner you start doing it, the better at slowing down this aging process,” he explains, adding, “Is toothpaste perfect? No, you’re still getting tooth decay with toothpaste, but you’re slowing down tooth decay.”

Hair changes about as fast as grass grows, which is to say it’s extraordinarily slow and not visible to anyone checking impatiently in the mirror every day. But during regular follow-up appointments, Harklinikken uses high-tech equipment to photograph and magnify the scalp and count new hairs and active follicles, which motivates users to adhere to the regimen. Too many people give up on treatments like Rogaine and low-level-light devices before they’ve had a chance to work, Dr. Senna said. Patients with tinea capitis typically present with patchy alopecia with or without scaling, although the entire scalp may be involved. Other findings include adenopathy and pruritus. Children may have an associated kerion, a painful erythematous boggy plaque, often with purulent drainage and regional lymphadenopathy. Posterior auricular lymphadenopathy may help differentiate tinea capitis from other inflammatory causes of alopecia. If the diagnosis is not clear from the history and physical examination, a skin scraping taken from the active border of the inflamed patch in a potassium hydroxide preparation can be examined microscopically for the presence of hyphae. Skin scrapings can also be sent for fungal culture, but this is less helpful because the fungi can take up to six weeks to grow.

In 1952, a New York dermatologist named Norman Orentreich invented hair plugs. He removed hair from the back of a patient’s head, where it still grew, and grafted it onto the front. In the decades since, the transplantation process has become more refined. Following the lead of the pioneering dermatologist Robert Bernstein, most doctors perform follicular-unit extraction; instead of crudely ripping up large parts of the scalp, they pluck and move individual follicular units.

While there can be numerous reasons behind the thinning of your hair, including certain hairstyles, excessive chemical processes, hereditary factors, and nutritional deficiencies, the most common is aging. But why does hair become thin as we age? Well, as we get older so do our hair follicles. With age, the size of hair follicles begins to shrink, meaning the rate of hair growth begins to slow down and, in some cases, ceases completely. Another reason for thinning hair lies in the production (or lack thereof) of estrogen as we age. Aside from regulating the reproductive system, estrogen plays a big part in hair growth. So, when we begin to produce less estrogen, there's less available to stimulate new hair growth (especially after old hair has shed), ultimately resulting in thin hair.